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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
         .one {
background-image: url(./R-C.jpg);
height: 500px;
background-repeat: no-repeat;
background-color: purple;
background-position: center;
}
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<body>
    <div class="one">背景居中</div>
</body>
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